Video on demand (display) (VOD) are systems which allow users to select and watch/listen to video or audio content such as movies and TV shows when they choose to, rather than having to watch at a specific broadcast time, which was the prevalent approach with over-the-air broadcasting during much of the 20th century.
Simple machines are used to make work easier. They are used in various places and times in our lives. They include: the pulley, screw, wheel and axle, wedge, lever, and the inclined plane. Compound machines are made up of two or more simple machines. Materials Activity 1: Discovering Simple Machines Parents bring simple machines that they will demonstrate for students such as pliers, hammers, screwdrivers, wrenches, wire cutters, small crowbars, scissors, saws, garden tools,
Although some people say that there are less than six simple machines (since a wedge can be considered an inclined plane that is moving, or a pulley is a lever that rotates around a fixed point), most authorities agree that there are in fact six types of simple machines.